Microwave communication devices such as, for example, WiMAX Customer Premises Equipment (CPE), WiMAX Subscriber Stations (SS) and WiMAX Mobile Stations (MS) are well known elements of a WiMAX communication system. Such devices are arranged to communicate with a WiMAX base station and offer wireless microwave connectivity over distances far in excess of that exhibited by WiFi systems.
Various signalling scenarios arise such as when a user first switches on the WiMAX device, or when such device performs a handover from a serving base station to a target base station, or indeed when the device performs network re-entry when coming out of its idle mode, and during location update. In such scenarios ranging signalling arises during which the device attempts to acquire correct timing offset and power adjustment values.
In returning its ranging response signal, the base station uses an initial ranging Connection Identifier (CID) common to all potential WiMAX devices such that each device has to decode each Media Access Control (MAC) Packet Data Unit (MPDU) even though the vast majority of such MPDUs will not be intended for, or be useful to, that particular device. This leads to various inefficiencies having regard in particular to speed of operation and power usage.